The long term goal of the studies proposed, is to understand the mechanism of respiratory syncytial virus (RSV) induced interleukin-8 (IL-8) expression, as it is related to nuclear factor activation. RSV infection in children results in 90,000 hospital admissions and 4500 deaths on an annual basis in the U.S. The exact mechanism of RSV induced inflammation and injury is not known but appears to involve an intense inflammatory response. IL-8, a potent chemotactic and activating agent for leukocytes, is produced in increased amounts during RSV infection of airway cells in vitro and in vivo. Preliminary studies indicate that NF-k-B activation is critical for RSV induced IL-8 gene expression. The working hypothesis of this grant states that RSV proteins activate NF-k-B and other nuclear transcription factors which act cooperatively in airway cells to induce IL-8 gene transcription. In order to test this hypothesis, the following specific aims are proposed: 1) identify cis-active regulatory elements in the 5' flanking region of the IL-8 gene which are responsive to RSV infection, 2.) Define the role of viral replication in RSV induced IL-8 gene transcription and nuclear factor activation, 3.) Determine the role tyrosine phosphorylation of NF-k-b subunits in RSV induced NF-k-B activation and IL-8 gene expression, and 4.) Define the role of individual RSV gene products in stimulating IL-8 gene transcription through nuclear factor activation. Studies will be performed on A549 cells (a human airway epithelial cell line) and in primary airway epithelial cells. Having gained an understanding of mechanism of RSV induced NF-k-B activation and IL-8 gene expression, future studies will focus on pharmacologic means of amiliorating RSV induced inflammation in the airway. The candidates long term plan will focus on defining the mechanism of viral induced inflammation and injury in the airway.